DIFFERENTIAL DIAGNOSIS IN LEARNING DISABILITIES

Summary

Principal Investigator: Richard K Olson
Affiliation: University of Colorado
Country: USA
Abstract: The long-range objectives of the Colorado Learning Disabilities Research Center (CLDRC) are the identification, characterization, validation and amelioration of reading disabilities and ADHD, the two most prevalent and often co-morbid disorders of childhood. To accomplish these objectives, the CLDRC employs a unique approach that assesses the extent to which genetic and environmental influences underlie these disorders, and that uses covariation in etiology to understand whether deficits in component skills of reading are manifestations of a single syndrome or represent separate subtypes. Test batteries that include psychometric measures of cognitive and academic abilities (Project I), reading, writing, and language processes (Project II), and ADHD and executive functions (Project III) will be administered to a sample of identical and fraternal twins and their siblings in which at least one member of each twin pair has a reading disability, to an independent sample of twins and their siblings in which at least one member of each twin pair has ADHD, and to a comparison group of twins and their siblings with no school history of reading disabilities or ADHD. Resulting data will be used to assess the etiologies of reading deficits (including word recognition skills, reading fluency, comprehension, and writing), ADHD, and their comorbidity, as well as their covariation with measures of phoneme awareness, phonological decoding, orthographic coding, vocabulary, listening comprehension, and executive functions. In order to map quantitative trait loci that influence learning disabilities, and conduct association and mutation analyses, blood samples will be obtained from families of all twin pairs (Project IV). Project V will assess response to computer-assisted instruction in 3 samples: early (K-4th) at-risk readers, 2nd - 4th grade twins identified with reading disabilities in Projects l-lll, and 4th grade twins with reading disabilities for whom we have extensive longitudinal assessments starting from preschool. Response to instruction in project V will also be studied in the Project IV molecular-genetic analyses. An administrative core unit will be responsible for coordinating the activities of the five research projects, ascertaining and scheduling subjects, obtaining questionnaire data and blood samples, and administering the Center budget. Reading disabilities and ADHD are important public health problems. The proposed research will advance our understanding of their etiology and remediation.
Funding Period: 2006-03-10 - 2010-11-30
more information: NIH RePORT

Top Publications

  1. ncbi Neuropsychological analyses of comorbidity between reading disability and attention deficit hyperactivity disorder: in search of the common deficit
    Erik G Willcutt
    Department of Psychology, University of Colorado at Boulder, CO 80309, USA
    Dev Neuropsychol 27:35-78. 2005
  2. ncbi Brain structure correlates of component reading processes: implications for reading disability
    Erin Phinney
    Department of Psychology, University of Denver, Denver, CO 80208, USA
    Cortex 43:777-91. 2007
  3. ncbi Genes, environment, and dyslexia. The 2005 Norman Geschwind Memorial Lecture
    Richard K Olson
    Department of Psychology, University of Colorado, UCB 345, Boulder, CO 80309, USA
    Ann Dyslexia 56:205-38. 2006
  4. ncbi Colorado longitudinal twin study of reading disability
    Sally J Wadsworth
    Institute for Behavioral Genetics, University of Colorado, 447 UCB, Boulder, CO 80309, USA
    Ann Dyslexia 57:139-60. 2007
  5. doi DeFries-Fulker and Pearson-Aitken model-fitting analyses of reading performance data from selected and unselected twin pairs
    Jesse L Hawke
    Institute for Behavioral Genetics, University of Colorado, Boulder, 447 UCB, Boulder, CO 80309 0447, US
    Behav Genet 38:101-7. 2008
  6. doi Do motivational incentives reduce the inhibition deficit in ADHD?
    Michelle A Shanahan
    Department of Psychology, University of Denver, CO 80208 0001, USA
    Dev Neuropsychol 33:137-59. 2008
  7. doi Relations among speech, language, and reading disorders
    Bruce F Pennington
    Department of Psychology, University of Denver, Colorado 80208, USA
    Annu Rev Psychol 60:283-306. 2009
  8. doi Phonological and semantic priming in children with reading disability
    Rebecca S Betjemann
    Institute for Behavioral Genetics, University of Colorado, UCB 447, Boulder, CO 80309 0447, USA
    Child Dev 79:1086-102. 2008
  9. pmc Parental education moderates genetic influences on reading disability
    Angela Friend
    Department of Psychology, University of Colorado at Boulder, Boulder, CO 80309, USA
    Psychol Sci 19:1124-30. 2008
  10. doi How neuropsychology informs our understanding of developmental disorders
    Bruce F Pennington
    Department of Psychology, University of Denver, 2155 S Race Street, Denver, Colorado 80208 4403, USA
    J Child Psychol Psychiatry 50:72-8. 2009

Scientific Experts

Detail Information

Publications32

  1. ncbi Neuropsychological analyses of comorbidity between reading disability and attention deficit hyperactivity disorder: in search of the common deficit
    Erik G Willcutt
    Department of Psychology, University of Colorado at Boulder, CO 80309, USA
    Dev Neuropsychol 27:35-78. 2005
    ..Slow and variable processing speed was characteristic of all 3 clinical groups, suggesting that measures of this domain may be useful for future studies that search for the common genes that increase susceptibility to RD and ADHD...
  2. ncbi Brain structure correlates of component reading processes: implications for reading disability
    Erin Phinney
    Department of Psychology, University of Denver, Denver, CO 80208, USA
    Cortex 43:777-91. 2007
    ....
  3. ncbi Genes, environment, and dyslexia. The 2005 Norman Geschwind Memorial Lecture
    Richard K Olson
    Department of Psychology, University of Colorado, UCB 345, Boulder, CO 80309, USA
    Ann Dyslexia 56:205-38. 2006
    ....
  4. ncbi Colorado longitudinal twin study of reading disability
    Sally J Wadsworth
    Institute for Behavioral Genetics, University of Colorado, 447 UCB, Boulder, CO 80309, USA
    Ann Dyslexia 57:139-60. 2007
    ..In addition, genetic correlations reached unity for both groups, suggesting that the same genetic influences are manifested at both time points...
  5. doi DeFries-Fulker and Pearson-Aitken model-fitting analyses of reading performance data from selected and unselected twin pairs
    Jesse L Hawke
    Institute for Behavioral Genetics, University of Colorado, Boulder, 447 UCB, Boulder, CO 80309 0447, US
    Behav Genet 38:101-7. 2008
    ..However, the PA selection formula may be more readily generalized to the multivariate case...
  6. doi Do motivational incentives reduce the inhibition deficit in ADHD?
    Michelle A Shanahan
    Department of Psychology, University of Denver, CO 80208 0001, USA
    Dev Neuropsychol 33:137-59. 2008
    ..Hence, as predicted by the inhibition theory, children with ADHD performed worse than controls irrespective of incentives...
  7. doi Relations among speech, language, and reading disorders
    Bruce F Pennington
    Department of Psychology, University of Denver, Colorado 80208, USA
    Annu Rev Psychol 60:283-306. 2009
    ..We evaluate which comorbidity models can be rejected or supported as explanations for why and how these three disorders overlap and what new data are needed to better define their relations...
  8. doi Phonological and semantic priming in children with reading disability
    Rebecca S Betjemann
    Institute for Behavioral Genetics, University of Colorado, UCB 447, Boulder, CO 80309 0447, USA
    Child Dev 79:1086-102. 2008
    ..These semantic deficits may contribute to both the word reading and the comprehension problems seen in children with RD...
  9. pmc Parental education moderates genetic influences on reading disability
    Angela Friend
    Department of Psychology, University of Colorado at Boulder, Boulder, CO 80309, USA
    Psychol Sci 19:1124-30. 2008
    ..We discuss the implications of these results for behavior genetic and molecular genetic research, for the diagnosis and remediation of reading disabilities, and for policy in public education...
  10. doi How neuropsychology informs our understanding of developmental disorders
    Bruce F Pennington
    Department of Psychology, University of Denver, 2155 S Race Street, Denver, Colorado 80208 4403, USA
    J Child Psychol Psychiatry 50:72-8. 2009
    ....
  11. pmc Gene X environment interactions in reading disability and attention-deficit/hyperactivity disorder
    Bruce F Pennington
    Department of Psychology, University of Denver, USA
    Dev Psychol 45:77-89. 2009
    ..However, they did not find a G x E interaction at the favorable end of the ADHD symptom dimension. The authors conclude with implications for future research...
  12. pmc Heritability of high reading ability and its interaction with parental education
    Angela Friend
    Department of Psychology, University of Colorado at Boulder, Boulder, CO 80309, USA
    Behav Genet 39:427-36. 2009
    ..This result provides a coherent account when considered alongside results of previous research showing that heritability for low reading ability decreased with lower levels of parental education...
  13. pmc Gender ratios for reading difficulties
    Jesse L Hawke
    Institute for Behavioral Genetics, University of Colorado, Boulder, CO, USA
    Dyslexia 15:239-42. 2009
    ....
  14. pmc A twin study of the genetics of high cognitive ability selected from 11,000 twin pairs in six studies from four countries
    Claire M A Haworth
    Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King s College London, London, UK
    Behav Genet 39:359-70. 2009
    ..41-0.60). Shared environmental influences were moderate (0.28, 0.19-0.37). We conclude that genetic variation contributes substantially to high g in Australia, the Netherlands, the United Kingdom and the United States...
  15. pmc How word decoding skill impacts text memory: The centrality deficit and how domain knowledge can compensate
    Amanda C Miller
    Department of Psychology, University of Denver, CO 80208, USA
    Ann Dyslexia 59:99-113. 2009
    ..This presents an exciting avenue to pursue for possible remediation of reading comprehension in children with word identification difficulties...
  16. ncbi Test of alternative hypotheses explaining the comorbidity between attention-deficit/hyperactivity disorder and conduct disorder
    Soo Hyun Rhee
    Department of Psychology, University of Colorado, Boulder, CO 80309, USA
    J Abnorm Child Psychol 36:29-40. 2008
    ..The results suggest that correlated risk factors are a better explanation for the comorbidity between ADHD and CD than a third, independent ADHD+CD subtype...
  17. pmc Testing for neuropsychological endophenotypes in siblings discordant for attention-deficit/hyperactivity disorder
    L Cinnamon Bidwell
    Department of Psychology, University of Colorado, Boulder, Colorado, USA
    Biol Psychiatry 62:991-8. 2007
    ..Neurocognitive deficits associated with attention-deficit/hyperactivity disorder (ADHD) might be useful intermediate endophenotypes for determining specific genetic pathways that contribute to ADHD...
  18. ncbi Toward a new neuropsychological model of attention-deficit/hyperactivity disorder: subtypes and multiple deficits
    Bruce F Pennington
    Department of Psychology, University of Denver, Denver, CO 80210 4638, USA
    Biol Psychiatry 57:1221-3. 2005
  19. ncbi Causal heterogeneity in attention-deficit/hyperactivity disorder: do we need neuropsychologically impaired subtypes?
    Joel T Nigg
    Department of Psychology, Michigan State University, East Lansing, Michigan 48824, USA
    Biol Psychiatry 57:1224-30. 2005
    ....
  20. ncbi Analyzing comorbidity
    Bruce F Pennington
    Department of Psychology, University of Denver, Denver, CO 80208, USA
    Adv Child Dev Behav 33:263-304. 2005
  21. ncbi TDT-association analysis of EKN1 and dyslexia in a Colorado twin cohort
    Haiying Meng
    Department of Pediatrics, Yale Child Health Research Center, Yale University School of Medicine, 464 Congress Avenue, New Haven, CT 06520 8081, USA
    Hum Genet 118:87-90. 2005
    ..Alternatively, the published findings of association with markers in EKN1 may reflect linkage disequilibrium with variation in another gene(s) in the region...
  22. ncbi Bivariate linkage scan for reading disability and attention-deficit/hyperactivity disorder localizes pleiotropic loci
    J Gayan
    Wellcome Trust Centre for Human Genetics, University of Oxford, UK
    J Child Psychol Psychiatry 46:1045-56. 2005
    ....
  23. pmc DCDC2 is associated with reading disability and modulates neuronal development in the brain
    Haiying Meng
    Department of Pediatrics, Yale Child Health Research Center, Yale University School of Medicine, New Haven, CT 06520, USA
    Proc Natl Acad Sci U S A 102:17053-8. 2005
    ..The statistical and functional studies are complementary and are consistent with the latest clinical imaging data for RD. Thus, we propose that DCDC2 is a candidate gene for RD...
  24. ncbi Genetic etiology of reading difficulties in boys and girls
    Sally J Wadsworth
    Institute for Behavioral Genetics, University of Colorado, Boulder, Colorado 80309, USA
    Twin Res Hum Genet 8:594-601. 2005
    ..3). A test for qualitative gender differences was also nonsignificant. Thus, these results provide little evidence for a differential genetic etiology of RD in boys and girls...
  25. ncbi Breakthroughs in the search for dyslexia candidate genes
    Lauren M McGrath
    University of Denver, Department of Psychology, Frontier Hall, 2155 S Race St, Denver, CO 80208, USA
    Trends Mol Med 12:333-41. 2006
    ..When causal variants are identified, they will need to be considered within a multifactorial framework, which is likely to involve gene-gene and gene-environment interactions, to make accurate predictions of diagnostic status...
  26. ncbi From single to multiple deficit models of developmental disorders
    Bruce F Pennington
    Department of Psychology, University of Denver, 2155 S Race St, Denver, CO 80208, USA
    Cognition 101:385-413. 2006
    ..It describes how this model evolved out of our attempts to understand two comorbidities, those between dyslexia and attention deficit hyperactivity disorder (ADHD) and between dyslexia and speech sound disorder (SSD)...
  27. ncbi Processing speed deficits in attention deficit/hyperactivity disorder and reading disability
    Michelle A Shanahan
    Department of Psychology, University of Denver, Denver, Colorado, USA
    J Abnorm Child Psychol 34:585-602. 2006
    ....
  28. ncbi Genes, language development, and language disorders
    Shelley D Smith
    Department of Pediatrics, University of Nebraska Medical Center, Omaha, Nebraska 68198 5456, USA
    Ment Retard Dev Disabil Res Rev 13:96-105. 2007
    ..Understanding these processes can form the basis for refined procedures for diagnosis and treatment...
  29. ncbi Genetic and environmental influences on word recognition and spelling deficits as a function of age
    Angela Friend
    Department of Psychology, 345 UCB, University of Colorado at Boulder, Boulder, CO 80309, USA
    Behav Genet 37:477-86. 2007
    ..However, the tests for an interaction between genetic influences on word recognition and spelling deficits as a function of age were not significant...
  30. ncbi Understanding comorbidity: a twin study of reading disability and attention-deficit/hyperactivity disorder
    Erik G Willcutt
    University of Colorado at Boulder, Boulder, Colorado 80309, USA
    Am J Med Genet B Neuropsychiatr Genet 144:709-14. 2007
    ....
  31. ncbi Etiology of the stability of reading difficulties: the longitudinal twin study of reading disabilities
    Raven L Astrom
    Institute for Behavioral Genetics, Department of Psychology, University of Colorado, Boulder, Colorado 80309, United States of America
    Twin Res Hum Genet 10:434-9. 2007
    ..65, indicating that common genetic influences account for approximately 75% of the stability between reading measures at the two time points...
  32. doi Does classroom separation affect twins' reading ability in the early years of school?
    William L Coventry
    School of Behavioural, Cognitive and Social Sciences, University of New England, Armidale, Australia
    Twin Res Hum Genet 12:455-61. 2009
    ..We conclude that, on average, early literacy in twins is not directly affected by their assignment to the same or different classrooms...